This invention pertains to a side trimmer knife which is formed from two used knife sections which have been reduced in thickness through repeated grinding to renew a peripheral cutting edge thereof and which are assembled to form a new knife and mechanically held together by means which functions to hold the knife sections together during repeated grindings of the faces of the newly-formed knife for repeated renewal of the peripheral cutting edges.
In a steel mill, the edges of strip steel are trimmed by a pair of side trimmer knives, each having a peripheral cutting edge which, during rotation thereof, cut the edges of the strip steel to form a strip of uniform width. Typically, a side trimmer knife is formed of a cylindrical body of hardened steel to have two peripheral cutting edges extending around the periphery of the exposed faces of the body, whereby, as one cutting edge becomes dull, the knife can be reversed on the arbor to bring the other cutting edge into use. After both cutting edges are worn, the knife is removed from the arbor and both exposed faces are ground to renew the sharpness of the peripheral cutting edges. A new cutting knife normally has a thickness of approximately 1.5 inches and, after repeated grindings have reduced the width thereof to approximately one-half the initial width, the knife does not have sufficient strength for continued cutting and the knife is scrapped.